1. Field of the Invention
The present invention generally relates effluent handling and processing apparatus, and more particularly concerns apparatus for filtering of solid material present in effluent before the effluent reaches a drain field, in order to prevent clogging of relatively small drain field finger openings such as are present in low pressure mound sanitary drainage systems.
2. Description of the Prior Art
Low pressure mound sanitary drainage systems are particularly useful in areas where soils are unable to meet percolation rates required for installation of a normal drain field. In low pressure mound sanitary drainage systems, effluent is pumped from an effluent tank downstream of a septic tank into a system of drain field fingers installed in a mound having drainage stone, sand, and other materials deposited inside. Usefulness is limited, however, by clogging of the openings in the drain field fingers by semisolid debris flowing from the septic tank or by solids such as leaves and grass which may enter the effluent tank during servicing or resulting from a loosely fitting effluent tank cover. As drain field finger openings become blocked, flow of effluent is reduced and the low pressure mound sanitary drainage system may be rendered inoperative.
In order to prevent the drain field finger openings from clogging, solid material present in the effluent should be removed prior flow into the drain field fingers. Currently available effluent apparatus include devices having a filter disposed in fluid connection to the input of an effluent pump, for instance those devices and systems described in U.S. Pat. Nos. 5,492,635; 5,427,679; and 4,439,323. In addition, there are presently available a number of filtering apparatus for septic tanks utilizing gravity feed filters, such as those described in U.S. Pat. Nos. 5,593,584; 5,580,453; and 5,382,357, and filters in fluid connection to the input of a septic pump, as described, for instance, in U.S. Pat. No. 5,582,716. Solid material present in effluent may be filtered by such devices, thereby helping to prevent clogging of openings in the drain field fingers, however, the filtering orifices defined by the devices frequently become clogged, requiring cleaning and servicing of the filtering apparatus.
Consequently, despite the availability of such devices, there exists a need in the art for an apparatus that is capable of filtering solid material present in effluent so that openings in drain field fingers remain open, but which includes a filter having filtering orifices which remain open and unclogged for an extended period of time, thereby requiring less frequent servicing and cleaning.